The Joint Accelerator Conferences Website (JACoW) is an international collaboration that publishes the proceedings of accelerator conferences held around the world.
TY - CONF AU - Pan, F. AU - Guo, H. AU - He, Y. AU - Jiang, T.C. AU - Li, C.L. AU - Lu, M. AU - Tan, T. ED - Michel, Peter ED - Arnold, André ED - Schaa, Volker RW TI - New Progress for Nb Sputtered 325 MHz QWR Cavities in IMP J2 - Proc. of SRF2019, Dresden, Germany, 30 June-05 July 2019 CY - Dresden, Germany T2 - International Conference on RF Superconductivity T3 - 19 LA - english AB - Comparing with bulk niobium cavities, the Nb/Cu cavities feature a much better stability at 4.5 K. Last year, two 325 MHz QWR copper cavities coated with biased DC diode sputterred Nb for CiADS has been accomplished at IMP. But vertical tests showed the cavities had low Q₀ at 4 K. To solve the issue, a new coating system was designed and built. The sputtering target was redesigned and manufactured. The coating parameters were selected again and auxiliary heating was used to control the coating temperature in the process of sputtering. The power and Ar pressure during coating were also carefully selected. The paper covers resulting film characters, vertical tests with the evolution of the sputtering process, and improvements we made since last year. PB - JACoW Publishing CP - Geneva, Switzerland SP - 621 EP - 623 KW - cavity KW - target KW - experiment KW - SRF KW - niobium DA - 2019/08 PY - 2019 SN - "" SN - 978-3-95450-211-0 DO - doi:10.18429/JACoW-SRF2019-TUP075 UR - http://jacow.org/srf2019/papers/tup075.pdf ER -